Syrian and Iraqi civilians were killed and injured in an attack on Tuesday morning in Syria.
(AP)

At least 37 people, including several children, were killed by Islamic State militants on Tuesday at a crossing often used by Syrian and Iraqi civilians seeking safety in northeastern Syria, officials said.

Some militants apparently blew themselves up at a Kurdish checkpoint in the first part of the attack. That checkpoint was maintained by the Syrian Democratic Forces (SDF), a force supported by the Kurds and the U.S. that fights ISIS.

Others attacked sleeping civilians in a temporary camp that was housing hundreds of people who had escaped ISIS-controlled areas. The militants “committed a massacre” against civilians as they tried to enter the SDF-controlled area, a spokesman for the Kurdish fighting force said.